Where is this wave?

In the first booklet I looked at when a video was filmed. This time the question is different: where?

One of the videos that spread after the 20 April 2026 Sanriku earthquake was a tsunami clip in which the water sweeps across a car park. The posts presented it as that day’s tsunami. Fact checkers soon showed that the footage was from 2011.

I took one step further and found the roof of the building it was filmed from. I used only pages anyone can open: frames of the video itself, aerial photos from GSI, Japan’s official mapping agency, OpenStreetMap records and a few calculations from coordinates. At each step I write down what I looked at, what I measured and what I could not know.

First I noted the event the footage belongs to, from an official source. I re-read the values on 29 September 2026 in the report the Japan Meteorological Agency (JMA) published for this earthquake.

““In the days after the earthquake the video started to spread again. According to AAP FactCheck’s article of 29 April 2026, a Brisbane-based Facebook account shared it as “the real tsunami not AI” after the magnitude 7.5 earthquake of the previous Monday.

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From the roof of which building was this filmed?

The fact checkers had already found the date. My question was about the place, and the answer had to be a coordinate. A district name or a description such as “near the port” does not answer it.

I also wrote down in advance when I would call it settled: when at least three independent clues point to the same building. A single address or a single resemblance is not enough.

■“■Searching YouTube for 石巻 津波 (Ishinomaki tsunami) brought up many copies of the same footage. The oldest copy I found was uploaded on 18 December 2011, and its description gives an address.

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““The Japanese broadcaster FNN published the same footage on its archive channel on 25 October 2012 and wrote far more detail in the description: the building, the road in front of it and the distance to a school.

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The water, the cars and the debris are gone the next day. I was looking for structures that would still stand in the same place years later. I paused the video every six seconds and took 45 frames, set aside the frames showing people, and noted this in the rest:

■■0:20, looking south. A car park with painted lines right in front, a wide road lined with power poles behind it, and at the back a row of pines and white factory buildings.

■■3:16, looking west. Two green spheres inside lattice frames and three or four tall, thin turquoise tanks. The thin tanks are closer than the spheres and to their right.

■■2:50 and 3:10. A wide green corrugated roof right below the camera. At 3:10 FNN itself marked the distant buildings with an orange frame.

■×■I typed the address into GSI’s map service. The search gave a point, but it fell at the edge of a road. Address points often mark the rough place of a plot or a block rather than a building.

■≠■OpenStreetMap has a record named 石巻ガス (Ishinomaki Gas) in the same district, and its point sits inside a large building. GSI’s address point is about 85 m away from it.

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That left two candidates: the address point and the OSM record. The structures in the video would decide between them.

∴∴In the current aerial photo the two large gas tanks stand west of the OSM record. The frame at 3:16 shows the tanks while looking west. In that frame the thin tanks are closer than the spheres, and in the aerial photo those small tanks sit between the spheres and the building.

■∴■I computed the distances from the OSM coordinates. The tanks are 172 m from the building, and the centre point of Minato Junior High School in OSM is 387 m away. Prefectural Road 240 runs east to west about 100 m south of the building. It is the wide road seen behind the car park in the frame at 0:20, looking south.

××Today’s photo is not enough on its own: much can change in fifteen years. I opened GSI’s aerial photos taken on 12 and 13 March 2011, the day after the tsunami.

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■∴■The 2011 photo shows four round structures, two turquoise and two grey. Today only the two turquoise tanks remain. The camera building’s roof is green in 2011, the same as the green corrugated roof right below the camera in the frames at 2:50 and 3:10. Today the same roof carries solar panels.

In the video the same roof shows at 3:10, right below the camera.

““After reaching my own result I read what the fact checkers wrote. AAP matched the place with Google Street View imagery from August 2011 and with the blue gas storage next to the office block. Tempo also confirmed through a visual match on Google Maps that the video was filmed at a gas company in Ishinomaki.

My route was different: instead of Street View I used GSI’s 2011 aerial photos, OSM records and distances from coordinates. Both routes lead to the same building.

∴∴The video was filmed on 11 March 2011 from the roof of the Ishinomaki Gas building in Myojincho, in Ishinomaki’s Minato district. In OpenStreetMap the building is recorded as 石巻ガス at 38.41661 N, 141.32574 E.

∴∴Three independent clues point to the same building: the tanks to the west, the road and car park to the south, and the green roof of 2011. By the rule I set at the start, the location is settled.

Next time someone sends you a video asking “where is this?”, try these six steps.

1. Turn the question into one sentence whose answer is a coordinate.

2. Treat the address in the description as a candidate, not as evidence.

3. Pick the structures in the video that will stay put for years. Do not use frames showing people.

4. Find the candidate on an official map and in OpenStreetMap, and compute directions and distances.

5. Compare with the aerial photo closest to the date of the event.

6. If at least three independent clues do not point to the same spot, write “I don’t know”.

1. 1. Japan Meteorological Agency (JMA), 災害時地震・津波速報 平成23年（2011年）東北地方太平洋沖地震 (quick report on the 2011 Tohoku earthquake). jma.go.jp/jma/kishou/books/saigaiji/saigaiji_201101/saigaiji_201101_01.pdf Source drawer
2. 2. takuro suzuki, YouTube, 18 December 2011. youtube.com/watch?v=aAIj2fws5O4 Source drawer
3. 3. FNN311, YouTube, 25 October 2012, 石巻市湊地区に押し寄せる津波【視聴者提供映像】. youtube.com/watch?v=K0rWPm9f3GQ Source drawer
4. 4. AAP FactCheck, “Old Japan disaster videos recycled after recent earthquake”, 29 April 2026. aap.com.au/factcheck/old-japan-disaster-videos-recycled-after-recent-earthquake Source drawer
5. 5. Tempo, “Fact Check: Misleading Videos Circulate After April 20, 2026 Japan Earthquake”, 27 April 2026. en.tempo.co/read/2100617 Source drawer
6. 6. Geospatial Information Authority of Japan (GSI), map service and tiles: current aerial photos (seamlessphoto), 東日本大震災後正射画像 (toho1, 12 and 13 March 2011), standard map. maps.gsi.go.jp. Source: GSI (出典 国土地理院) Source drawer
7. 7. OpenStreetMap, node 8484376919 (石巻ガス), ways 104429351 and 104429356 (gas tanks), 903069337 (石巻市立湊中学校), 941860082 and 941860085 (県道240号 石巻女川線). © OpenStreetMap contributors, ODbL Source drawer
8. Every source was checked again on 29 September 2026.